In recent years, a technique of attaching an input device referred to as a touch panel or a touch sensor to a display surface side of a display apparatus and sensing and outputting an input position when input operations are performed by contacting the touch panel with a finger or an input tool such as a touch pen has been known. Such display apparatuses having a touch panel are widely used in portable information terminals such as mobile phones in addition to computers.
One sensing method for sensing contact positions at which a finger or the like has contacted the touch panel is the electrostatic capacitance method. In an electrostatic capacitive touch panel, a plurality of capacitive elements each made up of a pair of electrodes disposed to be opposed to each other with a dielectric layer interposed therebetween, that is, a driving electrode and a sensing electrode are provided in a plane of the touch panel. Then, the input positions are sensed by utilizing the characteristics that the electrostatic capacitance of capacitive elements varies when performing input operations by contacting the capacitive elements with a finger or an input tool such as a touch pen.
In the display apparatus to which an input device such as a touch panel is attached, it is desirable to reduce electric resistance of the sensing electrodes for improving the sensing performance, and thus a conductive film such as a metal film is sometimes used as a material of the conductor pattern made up of the sensing electrode and a lead wiring electrically connected to the sensing electrode. Thus, in an electrode substrate included in the display apparatus and having a substrate and a conductor pattern made up of a sensing electrode and a lead wiring formed on the substrate, a protective layer is formed on the electrode substrate so as to cover the conductor pattern made up of the sensing electrode and the lead wiring for preventing corrosion of the sensing electrode.
When a protective layer is formed on the electrode substrate as described above, it is sometimes necessary to adjust the protective layer so as to have different film thicknesses between two regions on an upper surface of the substrate included in the electrode substrate, for example, between a certain region included in a peripheral region on an outer peripheral side of a display region and a region on an outer peripheral side of the substrate than the certain region or between the display region and the peripheral region.
As an example of a technique of adjusting a film so as to have different film thicknesses between two regions described above, Japanese Patent Application Laid-Open Publication No. 2010-181474 (Patent Document 1) describes a technique of forming an organic film pattern having a stepped structure in a thickness direction in a method of manufacturing a reflection type liquid crystal display apparatus.